Area-ratio principle for centrifugal pumps with low specific-speed

On the basis of area-ratio principle,a calculation method and formula for area ratio and eighth volute cross-sectional area in low specific-speed pumps designed with enlarged coefficient of flow-rate were proposed,so that the relationship between several parameters such as the area ratio,eighth volute cross-sectional area,enlarged coefficient of flow-rate,specific speed,and hydraulic parameters of the impeller and volute was obtained,and the problem of inconformity of design condition with optimal one due to unreasonable empiric determination of area ratio was solved.A practical example showed that the efficiency of pumps with low specific-speed could be improved by using the calculation method presented,so that the design theory of such pumps was substantiated.